1. Field of the Invention
The present invention relates to an electronic musical instrument providing plural tone-generation channels by which both an automatic accompaniment and a manual performance can be simultaneously played.
2. Prior Art
Recently, several kinds of electronic musical instruments each having an automatic accompaniment function have been developed. This kind of electronic musical instrument can simultaneously generate plural sounds, and therefore provides plural tone-generation channels. Thus, automatic-accompaniment sounds and manual-performance sounds can be respectively assigned to the different tone-generation channels in accordance with several kinds of the channel-assignment methods.
In the conventional electronic musical instrument, there are provided two kinds of tone-generation channels exclusively assigned to the manual-performance sounds and automatic-accompaniment sounds respectively in advance. Herein, each sound is assigned to each of the exclusive-use channels. In this case, even if the channels exclusively used for the automatic-accompaniment sounds are not used at all, these channels cannot be used for the manual-performance sounds, which raises a drawback in that the channel-use efficiency must be relatively low.
In order to efficiently use the tone-generation channels, a development has been made to invent a brand-new channel assignment technique in which some of common-use channels are arbitrarily and dynamically assigned to the automatic-accompaniment sounds and manual-performance sounds. In such case, however, it is necessary to maintain a balance between the numbers of the tone-generation channels respectively assigned to the automatic-accompaniment sounds and manual-performance sounds. For this reason, the maximum number of the channels used for one of two kinds of sounds must be restricted, or the predetermined priority order must be given to one of two kinds of sounds.
When the number of the sounds to be generated becomes extremely large with respect to one of two kinds of sounds, even the above-mentioned channel-assignment technique cannot respond to it well. Thus, there is another drawback in that the channel assignment must be made un-naturally, which may prevent the music from being played smoothly.